Modeling and Experimental Analysis on the Temperature Response of AlN-Film Based SAWRs

The temperature responses of aluminum nitride (AlN) based surface acoustic wave resonator (SAWR) are modeled and tested. The modeling of the electrical performance is based on a modified equivalent circuit model introduced in this work. For SAWR consisting of piezoelectric film and semiconducting substrate, parasitic parameters from the substrate is taken into consideration for the modeling. By utilizing the modified model, the high temperature electrical performance of the AlN/Si and AlN/6H-SiC based SAWRs can be predicted, indicating that a substrate with a wider band gap will lead to a more stable high temperature behavior, which is further confirmed experimentally by high temperature testing from 300 K to 725 K with SAWRs having a wavelength of 12 μm. Temperature responses of SAWR's center frequency are also calculated and tested, with experimental temperature coefficient factors (TCF) of center frequency being -29 ppm/K and -26 ppm/K for the AlN/Si and AlN/6H-SiC based SAWRs, which are close to the predicted values.